JPH0325356A - Wafer inspecting method - Google Patents

Abstract

PURPOSE:To accurately inspect a wafer which has a resist film of simple constitution from on the substrate surface by generating heterogeneous reflected light beams as reflected light from a large-grain wiring pattern and reflected light from foreign matter when the wafer is inspected. CONSTITUTION:The wafer is inspected by forming a resist film which contains dye having its absorption band at the wavelength of incident light 4 used for the inspection of a semiconductor device 1, e.g. 400 - 700nm on the wiring pattern 2 on the substrate 1 or the surface of the foreign matter 3. When the foreign matter is not present, almost all of irregularity reflected light reflected by the unevenness 2 of the wiring pattern 2 is absorbed by the resist film 6 and reflected light 5 from the film 6 formed on the surface of the pattern 2 never becomes irregularly reflected light. If there is the foreign matter 3, almost all of the irregularity reflected light from the unevenness 2a of the pattern 2 is absorbed by the film and the reflected light never becomes irregularity reflected light, but the reflected light 5 from the film 6 which is formed on the surface of the foreign matter 3 and has large curvature becomes irregularly reflected light, so that this case can securely be discriminated from the case wherein the foreign matter is absent.

Description

[Detailed Description of the Invention] [Summary] Regarding the improvement of a method for inspecting defects in wiring patterns with large grains, a resist film that can be easily and easily detected is used to detect defects in wiring patterns and foreign substances on the surface of a semiconductor substrate. form on top;
The purpose is to provide a wafer inspection method that enables accurate wafer inspection, and it is a wafer inspection method that inspects the presence of defects and foreign substances in wiring patterns formed on the surface of a semiconductor substrate, and is used for the above inspection. A film containing a material having an absorption band at the wavelength of incident light is formed on the surface of the wiring pattern or the foreign object.

[Industrial application field]

The present invention relates to an improvement in a method for inspecting defects in wiring patterns with large drain.

In recent years, in qualitative foreign particle inspection using automatic wafer inspection equipment, when inspecting a film with large grains such as aluminum or polysilicon formed on the surface of a semiconductor substrate, it is difficult to detect irregularly reflected light from irregularities caused by the grains and from foreign particles. This makes it difficult to distinguish the reflected light from the diffusely reflected light, making it difficult to perform accurate wafer inspection.

Under the above circumstances, there is a need for a wafer inspection method that can reduce the diffusely reflected light from the unevenness caused by these grains when inspecting films with large grains such as aluminum or polysilicon. .

[Conventional technology]

A conventional wafer inspection method will be explained in detail with reference to FIGS. 2 and 3.

FIG. 2 is a diagram showing a schematic structure of an automatic wafer inspection apparatus, in which a light beam 7a emitted from a light source 7 is reflected by a half mirror 8, and an incident light beam 4 condensed by a condensing lens 9 is directed to a semiconductor substrate below. 1, and the reflected light 5 from the surface of the semiconductor substrate 1 is transmitted through the half mirror 8, which is provided above.
Is it by a comparative inspection method that compares data obtained by receiving light with a D camera IO and processing image data of wiring patterns of adjacent semiconductor chips formed on the semiconductor substrate 1 by a computer?
Alternatively, the wiring pattern is inspected by a comparative inspection method in which image data of the wiring pattern received by the CCD camera 10 is compared with design data of the wiring pattern.

However, when the surface of the semiconductor substrate 1 is irradiated with the incident light 4, as shown in FIG. In the case of light, the reflected light 5 from the foreign object 3 irradiated with the same incident light 4 also becomes diffusely reflected light, making it difficult to distinguish them even with the naked eye, and it is impossible to distinguish them with automatic wafer inspection equipment. It is now possible.

[Problem to be solved by the invention]

In the conventional wafer inspection method described above, when the surface of the semiconductor substrate is irradiated with incident light for wafer inspection, the surface of the wiring pattern is uneven and the reflected light from the wiring pattern becomes diffusely reflected light. However, there is a problem in that it is difficult to distinguish the reflected light from the diffusely reflected light from a foreign object irradiated with the same incident light even with the naked eye, and it becomes impossible to distinguish it using an automatic wafer inspection apparatus.

The present invention enables accurate wafer inspection by forming a resist film that can be simply and easily formed on the wiring pattern and foreign matter on the surface of a semiconductor substrate. The purpose of this study is to provide a wafer inspection method.

[Means to solve the problem]

The wafer inspection method of the present invention is a wafer inspection method for inspecting the presence or absence of defects and foreign substances in wiring patterns formed on the surface of a semiconductor substrate, and includes a material having an absorption band at the wavelength of incident light used for this inspection. The structure is such that a film is formed on the surface of this wiring pattern or foreign matter.

[Effect]

That is, in the present invention, a film containing a material having an absorption band at the wavelength of incident light used for inspecting the semiconductor substrate is formed on the surface of the semiconductor substrate to inspect the wiring pattern for defects and foreign matter. Most of the diffusely reflected light reflected from the unevenness caused by the wiring pattern is absorbed by this resist film, and the reflected light from the resist film formed on the surface of the wiring pattern does not become diffusely reflected light, but it is reflected from the surface of the foreign object. The reflected light from the resist film having a large curvature becomes diffusely reflected light and can be reliably distinguished.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

The automatic wafer inspection device used in this example is a conventionally used Wi as shown in FIG. In this example, a resist film containing a dye having an absorption band at the wavelength of the incident light 4 used for inspecting the semiconductor substrate 1, for example 400 to 700 nm, such as TSMR-8800 manufactured by Tokyo Ohka Co., Ltd., is used. Since the inspection is performed by forming a film with a thickness of about 1 μm on the surface of the wiring pattern 2 and the foreign matter 30 of the semiconductor substrate 1, if the foreign matter 3 is not present, the unevenness 2a of the wiring pattern 2 as shown in FIG. Most of the diffusely reflected light reflected by the resist II #6 is absorbed by this resist II #6, and the reflected light 5 from the resist film 6 formed on the surface of the wiring pattern 2 does not become diffusely reflected light, so there is no diffusely reflected light in the reflected light 5. .

In the event that a foreign substance 3 is present, most of the diffusely reflected light reflected by the unevenness 2a of the wiring pattern 2 will be absorbed by this resist film 6, as shown in FIG. Although the reflected light 5 from the resist film 6 does not become diffusely reflected light, the reflected light 5 from the resist film 6 with a large curvature formed on the surface of the foreign object 3 becomes diffusely reflected light and can be reliably distinguished.

To form such a resist film 6 on the surface of the semiconductor substrate 1, a conventionally used spinner is used to apply the resist, but when a short spin for about 3 seconds is performed, the resist film 6 is formed on the surface of the semiconductor substrate 1. Since the resist film 6 has a flat surface shape different from the shape of the wiring pattern 2 or the foreign matter 3, a normal 15 to 20 second coating is performed to make the surface shape of the resist film 6 similar to that of the wiring pattern 2 or the foreign matter 3. Alternatively, it is necessary to make the shape similar to that of the foreign object 3.

After the inspection is completed, resist II #6 is removed using this resist stripping agent to complete the inspection.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a resist film with an extremely simple structure is formed on the surface of a semiconductor substrate and the surface of the wafer is inspected. It is possible to make the reflected light from foreign objects into different reflected light, which has the advantage of making it possible to accurately inspect the wafer, and it is a wafer that can be expected to have a significant economic and reliability improvement effect. Testing methods can be provided.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention, FIG. 2 is a diagram showing a schematic structure of an automatic wafer inspection apparatus, and FIG. 3 is a side sectional view showing a conventional wafer inspection method. In the figure, l is a semiconductor substrate, 2 is a wiring pattern, 2a is unevenness, 3 is a foreign object, 4 is incident light, 5 is reflected light, 6 is a resist lator, 7 is a light source, 7a is a light beam, 8 is a half mirror 9 10 is a condensing lens, and 10 is a CCD camera. ta+ X If the object does not exist, fbl If the foreign object exists, go to f.・f1 Side view showing the schematic structure of automatic wafer inspection equipment Side sectional view showing the conventional wafer inspection method Figure 3

Claims (1)

[Claims] Wiring pattern (2) formed on the surface of a semiconductor substrate (1)
A wafer inspection method for inspecting the presence or absence of defects and foreign matter (3) in the wiring pattern (2), the film (6) containing a material having an absorption band at the wavelength of the incident light (4) used for the inspection. )
A wafer inspection method characterized in that the method is performed by forming a foreign substance on the surface of the foreign substance (3).